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Im assuming you want to do this for testing out your CGI scripts??
Im not familiar with any such tool in Unix, but Perl provides you a
ready-made module for just this kind of thing. The module is WWW::Mechanize.
Using this, you can design custom-made Perl scripts using methods(functions)
in the module.

If this is an option for you, go to
http://search.cpan.organd search for WWW::Mechanize. he site contain the complete help doucments
regarding the same.